Since polyester containers such as food containers, beverage bottles, pharmaceutical containers, cosmetic containers and the like made of polyester plastic materials combine the advantages of low cost and durability with ease of fabrication, there is an increasing demand for polyester containers. In many applications the polyester containers must be colored not only to make the container aesthetically pleasing, but also to minimize light transmittance and thereby protect the container contents from light degradation. As a result, several colorants have been developed for polyesters used in the container industry. However, present colorants suffer from a number of important disadvantages. For example, some dyes and pigments used to color polyesters are costly and thereby greatly add to the cost of the containers. Other colorants, such as iron oxide, cause the polyester to become clouded thereby obscuring from view the container contents. Still other colorant systems allow high light transmittance in the ultraviolet light range, e.g. 300 nm. to 450 nm., which tends to degrade the light sensitive contents of the container. Finally, other colorants tend to leach from the polyester container into the container contents and therefore cannot be used with foods, drugs and cosmetics.
Accordingly, it is an object of the present invention to provide a polyester colorant that is non-extractable from the polymer.
It is a further object of the present invention to provide a colored polyester which exhibits low light transmittance in the ultraviolet range.
It is a still further object of the present invention to provide a low cost, amber-colored polyester having greater clarity than other amber-colored polyesters.
These and other objects of the present invention will be apparent to one of ordinary skill in the art from the summary and detailed description which follows.